Frictional driving-gear.



L, ,w l 1.. A mw H l. u n .v 4 7 m m. om nn,... H 70A D.. S n A .4 m we T N 1 M nm P Am -w N OGM TNT. HIM G VS UID ORE RDW.. B F ULN DAO UNH Mmm DMN... my, ,F .4v oo 6P 5. oo oo n Nv zuzeses No. 885,684. PATBNTBD APR. 21, 1908.

D.' MOD. BROUGHTON. PRIGTIONAL DRNING GEAR.

APPLICATION FILEDASBPTJL 1907.

4 SHEETS-SHEET 2.

1HE NoRRls PETERS a.. wAsHlNsnm, n. c.

110.885,68@` PATENTED A1=R.21,'19f08.v

D.Y MoD. BROUGHTON.

PRIGTIONAL DRIVING GEAR. APPLIOAT'ION FILED smv:` 14, 1901.

4 SHBBTSQSHEBT a;

TH: Nalzls Firmas cu., WASHINGTON, n. c.

. PATENTED APR. 21, 1908.y D. Mon. BRoUGHToN. v AFRIGTIONAL' DRIVING GEAR.

APPLICATION FILED SEPT 14 1907 4 SHEETS-SHEET 4.

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UNITED STATES PATENT OFFICE.

DENIS MGDONNELL BROUGHTON, OF WOODFORD GREEN, ENGLAND, ASSIGNOR OF ONE-HALF TO THE BRITISH SIGARERA LIMITED, OF LONDON, ENGLAND.

FRICTION AL DRIVING-GEAR.

Specification of Letters Patent.

Patented April 21, 1908.

ence to that class of frictional driving gear in which a single pulley or wheel loosely mounted upon the shaft to be driven is adapted for frictional connection thereto when it is desired to get the shaft -in rotation.

Hitherto gearing of the kind above referred `to has usually comprised a loose pulley mounted upon the shaft to be driven, in combination with an internallyv and concentrically arranged friction strap; said strap being normally held in the operative positionthrough suitable connections-by means of a loose tapered collar adapted to be moved along the shaft between limiting stops. A disadvantage consequent upon this arrangement of parts has been the liability of the friction strap to become worn, and owing to the fixed diameter of the tapered collar, it must have some means of adjustment to compensate for this wear.

The object of the present invention is to obviate the foregoing disadvantage in a simple and effective manner, to insure perfect reliability in action as wellas to prevent any failure of action through any parts becoming loose or worn when in use.

The invention consists essentially in disposing the friction strap so that it normally tends to en age firmly with the inner periphery of the oose pulley or wheel, and in arranging the sliding collar so that it is only brought into operation for releasing the strap from frictionalcontact with said loosev pulley, or wheel.

The accompanying drawings are in illustration of my invention.

Figure 1 is a side elevation of a belt driven frictional gear constructed in accordance with my improvements and showing the friction strap in its operative position j Fig. 2 is a similar view to Fig. 1 but showing the friction strap out of engagement with the driving pulley 5 Fig. .3 is a transverse sectional elevation on the line A-A in Fig. 1

Fig. 4 is a side elevation of a slightly modified form of my invention, and Fig. 5 is an elevation taken at rightangles to Fig. f1; Figs. 6 and 7 are respectively a side view and sectional plan of a further slightly modified form of the present invention. Like letters of reference design ate the same or similar parts in the various figures.

Accordin to the forms of my invention illustrated, I varrange upon the shaft a to be driven a loose pulley or wheel b of metal or other suitable material, said ulley or wheel t being adated for free revo ution between the collars c, c formed upon or fixed to, as shown, the shaft a. The pulley or wheel b is preferably made with its periphery or rim more or less to one side of a sup orting disk d or spokes at right angles tot e hub e, so that a short cylinder or casing is constituted, one end being closed in by the said disk d. Inside the casing so constituted I arrange a concentric stra f, preferably a steel spring, the two ends o which are secured, as hereinafter more fully described, so that the normal tendency of the strap is to expand as `much as may be required to bring itself into frictional engagement with the inner periphery of the loose pulley, or wheel, b, irrespective of wear on any part.

A strip of leather g or the like is secured to l the outer surface of the strap f to insure -increased friction and to prevent wear of the metallic surfaces, and it is conveniently fixed to the said strap f by riveting as shown at h, h, in Figs. 1 and .2, or it may be otherwise attached. One end 'i of the strap f is firmly connected to the end of an arm y' extending radially outward from the boss or collar c', securely held in position by means of a set screw 7c upon the shaft a to be set into rotation, to within a short distance of the inner periphery of the loose pulley orvwheel b. The free end l of the strap f is hin `ed to the outer end of the short arm m of a ell-crank lever pivotally mounted at m near the outer extremity of the aforesaid arm j; the other, or'longer, arm m2 of the bell-crank lever extending inwardly, and somewhat tangentially towards the shaft a, but does not come into actual contact therewith, as will be clearly understood from Figs. 1, 2 and 4, of the accompanying drawings.

To insure more perfect expansion of -the steel strap f when the sliding collar n is clear of the bell-crank lever and consequently more perfect engagement all over the surface of the strapf with the inner rim of the loose pulley or wheel I), I attach to the shorter arm m of the bell-crank lever above described a strong metal rod o, as will be best seen on reference to Figs.` 1, 2 and 4. To the free end of this rod 0 is attached one end of a tension spring p, the other end of which is secured to a short projecting arm g formed u on the boss c" carrying the radial arm abjove described. Or, to further assist the expansive tendency of the strap f to evenly engage all round the inner periphery of the loose pulley or wheel b, I may provide the free end Z of said strap with a hinged tonguepiece or link flap l (Figs. 6 and 7), which is hinged at Z2 to the strap end and at its free end to the short arm m of the bell-crank lever above described. In this case and when applied to light speed gears I may dispense with the tension spring and its connections, as shown in Fig. 6.

To disengage the strap f from contact with the rim of the loose pulley or wheel, I arrange upon the shaft a and adapted to be moved towards and away from the collar c carrying the radial arm a freely fitting collar or sleeve -n one end of which r (Figs. 3 and 5) that next the pulley, is somewhat ta ered down or truncated. When the sliding co lar n is moved towards the pulley, in any convenient manner, for example, by means of a pivoted lever s, shown in dot and dash lines in Fig. 3 and in full lines in Fig. 5, furnished with a forked end engaging in a groove t in said collar n, the truncated end 1' is forced between the longer arm m2 of the bell-crank lever and the shaft a itself. This operation turns the bell-crank arm upon its pivot m for a short distance and draws the friction strap j' away from the pulley or wheel b.- To return the parts, the sliding collar n is moved in the op osite direction, a stop u (Figs. 8 and 5) being provided to limit its movement away from the gearing.

In Figs. l to 3 I have shown a frictional driving gear adapted for operation by belt driven power, while Figs. 4 and 5 illustrate a clutch actuated by toothed gearing from any convenient source of energy, for example, an electric inotor-not shown. i) (Figs. 4 and 5) is a toothed rim formed upon and integral with thepulley or wheel b meshing with a small pinion 'w fixed upon the motor shaft ac.

From the foregoing it will be seen that by my improvements a simple self-adjusting and very efiicient frictional driving gear is provided.

The details of construction may be varied as may be found desirable to adapt my imrovements to different working conditions,

for example, I may dispense with the tensionv spring p and its connections in cases where the driving gear is not subjected to great working variations. Further, two, three or more gears constructed as described but of different speeds maybe arranged side by side upon the shaft to be driven.

that I claim as my invention and desire to secure by Letters Patent, is

1. In a clutch, the combination of a shaft, a pulley mounted on said shaft and provided with a rim, a resilient strap, the tension of whichY is normally outward to inipinge the inner surface of the rim, an arm fixed to the shaft and connected to the lstrap, a pivotally mounted lever pivotally connected to the opposite end. of the strap, a slidable beveled member operable in the path of movement of the pivotally mounted arm to withdraw the strap out of contact with the rim.

2. In a clutch, the combination of a shaft, a pulley loosely mounted on said shaft and provided with a rim, a resilient strap, the tension of which is normally outward to iminge the inner surface of the rim, an arin fixed to the shaft, and connected to the end of the strap, a bell crank lever pivoted to the arm and pivotally connected to the opposite end of the strap, a spring norinally pulling` one arm of the bell crank lever toward the shaft to increase the friction between the strap and rim, and a slidable element operable in the path of movement of the bell crank lever to rock the same to disen gage the strap from the inner surface of the rim.

3. In a clutch, the combination of a shaft, a pulley mounted thereon, a resilient stra) normally in frictional contact with the pufley, means connecting one end of the strap to the shaft, a pivoted Iever connected to said latter means and the opposite end of the strap, and a sliding beveled collar operable in the path of movement of the pivoted lever to disengage the strap fioin the pulley and thereby free the said pulley on the shaft.

4. In a clutch, the combination of a shaft, a pulley mounted thereon and having an out wardly extending rim, an arm fixed to the shaft and connected at its outer end to the strap, a bell crank lever pivotally mounted on the arm, one member being pivoted to the strap and the other member of said bell crank lever being located in the path of movement of a releasing element, and a sliding releasing eleinent for operating the bell crank lever to release the strap from contact with the inner surface of the outwardly extending rim.

5. In a clutch, the combination withv a shaft, a pulley loosely mounted on said shaft and having a rim, a resilient strap iioimally engaging the inner surface of the rim, an arm fixed to the shaft and connected at its outer end to one end of the strap, a bell crank lever pivoted to the arm, one member of the bell crank lever being pivoted to the opposite end strap from Jrictional en agement With the of the strap, the other member of the bell rim to free the pulley on t e shaft. crank lever being in the path of movement of In Witness whereof 'l have hereunto set In a releasing element, an arm extending from hand in the presence of tWo witnesses.

the bell crank lever, a spring connected to DENIS MGDONNELL BROUGH'ION. Y the latter arm and a projection ixed to the Witnesses: I shaft, and a slidable element engaging one ALFRED G. BRATTON,

arm of the bell crank lever to release the RICHARD GOERKE. 

